Triethylamine → (3R,5S)-1-allyloxycarbonyl-5-[1-hydroxy-(imidazo[5,1-b]thiazol-3-yl)methyl]-3-methanesulfonyloxypyrrolidine

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Reaction Steps

Triethylamine (0.25 ml) and 0.12 ml of methanesulfonyl chloride are successively added to a solution of 457 mg of crude (3R,5S)-1-allyloxycarbonyl-3-hydroxy-5-[1-hydroxy-1-(imidazo[5,1-b]thiazol-3-yl)methyl]pyrrolidine (stereoisomer A) in 12 ml of dry THF in an argon atmosphere at 3° C., and the mixture is stirred in this state for 30 min. A 5% aqueous sodium hydrogencarbonate solution (30 ml) is added thereto, and the mixture is extracted with 100 ml of ethyl acetate. The organic layer is washed with saturated saline, dried over magnesium sulfate, and filtered, and the solvent is removed by evaporation under reduced pressure to give a slightly cloudy orange brown oil. This oil is purified by flash column chromatography on silica gel (ethyl acetate:methanol=92:8) to give 344 mg of crude (3R,5S)-1-allyloxycarbonyl-5-[1-hydroxy-1-(imidazo[5,1-b]thiazol-3-yl)methyl]-3-methanesulfonyloxypyrrolidine (stereoisomer A) as a milky white amorphous material.

Provenance & Evidence